where the multiplicative constant underlying \(O(\cdot )\)  depends on \(d, \sigma \) , and \(V\) .
In the univariate case, we can deduce from [1]} that
\(\mathcal {R}\big (\hat{f}^{1}_{n, V}, f^{*}\big ) \le C \Big (\frac{\sigma ^2 V^{\frac{1}{2}}}{n}\Big )^{\frac{4}{5}} + C \frac{\sigma ^2}{n} \log n,\) 
